It has been demonstrated by investigations that components such as water vapor and oxygen in the air has great influence on the service life of OLEDs. This is mainly because metals used as cathodes, such as aluminum, magnesium, calcium, etc., are relatively active and will easily react with permeated water vapor. Furthermore, water vapor will be also subjected to chemical reaction with a hole transport layer and an electron transport layer (ETL) to cause device failure. Therefore, the service life of a device may be greatly elongated, as long as an OLED is subjected to effective packaging to separate respective functional layers of a device from components such as water vapor, oxygen, and the like in the atmosphere. However, the previously reported thin film packaging includes various processes, such as inorganic film packaging, organic film packaging, inorganic-organic film combined packaging, etc., and none of them can achieve 100% barrier of water vapor and oxygen.
Therefore, how to provide an OLED packaging method, which can effectively have the functions of water vapor barrier and oxygen absorption, appears to be extremely important.